1. Field of the Disclosure
The present disclosure relates generally to scanners, and more specifically, to an optical system for a scanner.
2. Description of the Related Art
A typical scanner includes one or more scan heads. A first scan head design employs an array of thin rod lenses to form a line image onto a 1:1 ratio sensor array, referred to as a contact image sensor. A second scan head design employs folding mirrors to form a reduced image via a lens onto a sensor array and is often referred to as an optical reduction system. The optical reduction system holds many advantages over the contact image sensor in terms of image quality. However, a scan head having an optical reduction system is typically bulkier than a scan head having a contact image sensor. Further, too many reflections may result in undesired ghosting of the scanned image.
Conventional document scanners may include a scan head contained within a flatbed chamber. An automatic document feeder (ADF) window may also be used to perform a simplex scan or a duplex scan with a re-circulating paper path. It is desired that the vertical dimension of such scan heads is small enough to minimize the size of the scan head. Alternatively, a scanner may employ a scan head that is positioned along a media path of an ADF as is known in the art. It is often desired that the horizontal dimension of such scan heads is also compact. Accordingly, it will be appreciated that an optical system that achieves compact dimensions for a scanner while maintaining high optical image quality is desired. As a result, it will be appreciated that a scan head that achieves high image quality while being relatively easy to manufacture is also desired.